The following relates to a method and system for determining information relating to the occupancy of a space by one or more objects. The method and system have been devised for determination of queue lengths and other kinds of waiting times. However the method and system have other applications such as the determination of a number of vehicles in a car park or parking lot and the determination of the occupancy of other spaces by objects other than people.
The information determined using the method and system may be any information that is useful in determining occupancy including time of arrival of objects into the space and time of departure.
Some information relating to queue length can be obtained from a camera viewing a queuing area. For example, a camera or other optical sensor may be used to view people queuing at a supermarket checkout. Image data from the camera or other sensor can be processed to provide an estimate of the queue length. However there are many sources of possible error in estimates obtained from image or other sensing data alone.
For example, using image data, it is not always possible to resolve groups of people standing close together to determine the number of individuals. Furthermore, a number of individuals is frequently not indicative of queue length, for example when two individuals shop together. Therefore, for an accurate determination of queue length, it is preferable in certain embodiments to define “shopping units” each of which may comprise more than one individual. A shopping unit may comprise a family group for example.
The same potential inaccuracies arise when using image data to determine occupancy of other kinds of space by people or objects. The potential for inaccuracies is particularly significant if the information to be determined is not simply the number of objects or individuals, but rather a number related to groups of individuals such as shopping units.